1. Field of Invention
The invention is related to a method of measuring a surface structure of a display device, and is particularly related to a method of measuring a size of a surface structure of a display device, which is applying to the field of display device.
2. Description of Related Art
Recently, the trend of the display products is light, thin, small, and high resolution. However, these requirements cause difficulties in design, fabrication and size measurement of the internal structures of the display device. That is, in order to dispose more pixels in a smaller space to provide a higher resolution, the interval space between the structures is not sufficient. Therefore, the precision and the reproducibility of the size measurement results of the structures are poor. Furthermore, it is difficult to control the processes by adjusting the parameters according to the size measurement results, thus the production yield and the throughput are reduced.
FIG. 1 is a schematic view of a display device and an optical measuring apparatus for a surface structure. Referring to FIG. 1, the display device includes a first substrate 210, a patterned light-shielding layer 214, at least one first protrusion 218, and at least one second protrusions 2184. The first substrate 210 has a first surface 212. The patterned light-shielding layer 214 has a plurality of openings 216 and disposed on the first surface 212 of the first substrate 210. The first protrusion 218 correspondingly covers the openings 216 of the patterned light-shielding layer 214 and a portion of the patterned light-shielding layer 214. The second protrusions 2184 are disposed in the patterned light-shielding layer 214. The optical measuring apparatus for a surface structure (not shown) includes a positional movable platform (not shown), a light source (not shown), an operation processing unit (not shown), and a microscope lens 100, and the microscope lens 100 includes a dichroic mirror (not shown), a first light detector (not shown), and a second light detector (not shown).
FIG. 2 is a schematic cross-sectional view of the optical measuring apparatus for a surface structure and the first substrate 210 of the display device along line A-A′ in FIG. 1. Referring to FIG. 2, the positional movable platform carries the first substrate 210 of the tested display device to posit the microscope lens 100 directly over the patterned light-shielding layer 214 on the first substrate 210. The light source emits a parallel light beam 102 toward the patterned light-shielding layer 214, and the parallel light beam 102 is divided into a measuring light beam and an interference light beam by the dichroic mirror. The measuring light beam irradiates the patterned light-shielding layer 214 on the first substrate 210, a reflected light reflected from the patterned light-shielding layer 214 to the microscope lens 100 is received and converted into a first signal by the first light detector, and the interference light beam is received and converted into a second signal by the second light detector.
FIG. 3 is a schematic cross-sectional view of the optical measuring apparatus for a surface structure and the first substrate 210 of the display device along line A-A′ in FIG. 1. Referring to FIG. 3, the positional movable platform is moved to posit the microscope lens 100 directly over the first protrusion 218 on the first surface 212 of the first substrate 210. The light source emits a parallel light beam 102 toward the first protrusion 218, and the parallel light beam 102 is divided into a measuring light beam and an interference light beam by the dichroic mirror. The measuring light beam irradiates the first protrusion 218 of the first substrate 210, a reflected light reflected from the first protrusion 218 to the microscope lens 100 is received and converted into a third signal by the first light detector, and the interference light beam is received and converted into a fourth signal by the second light detector.
FIG. 4 is a schematic cross-sectional view of the optical measuring apparatus for a surface structure and the first substrate 210 of the display device along line A-A′ in FIG. 1. Referring to FIG. 4, the positional movable platform is further moved to posit the microscope lens 100 directly over the second protrusion 2184 on the first surface 212 of the first substrate 210. The light source emits a parallel light beam 102 toward the second protrusion 2184, and the parallel light beam 102 is divided into a measuring light beam and an interference light beam by the dichroic mirror. The measuring light beam irradiates the second protrusion 2184 of the first substrate 210, a reflected light reflected from the second protrusion 2184 to the microscope lens 100 is received and converted into a fifth signal by the first light detector, and the interference light beam is received and converted into a sixth signal by the second light detector. The first signal, the second signal, the third signal, the fourth signal, the fifth signal, and the sixth signal are received and operated by the operation processing unit to output the height of the first protrusion 218 and the height of the second protrusion 2184 on the first surface 212 of the first substrate 210.
However, in order to dispose more pixels in a smaller space to provide a higher resolution, a width of the light-shielding layer disposed between the pixels should be reduced. Therefore, the light-shielding layer can not provide a single plane having a sufficient width, and a uniform reflected light is not obtained as the measuring light beam irradiates the patterned light-shielding layer 214. Accordingly, the precision and the reproducibility of the size measurement results of the structures are poor. Furthermore, it is difficult to control the processes by adjusting the parameters according to the size measurement results, thus the production yield and the throughput are reduced.